Taupo Rd 5
Round 5 at Taupo was an expensive weekend and one I don’t want to repeat any time soon. It started in Feilding at 4am Friday with the team getting up early to get to the Taupo track by 8:30 to make practice, due to fitting the new sway bar and brake pads I needed the time to get use to the sway bar and bed-in the the new pads.
When we arrived we were greeted with rain and lots of it. So we set up the gazebos ands got to work setting the car up for the wet conditions. morning practice went well, learining that the new sway bar was really to hard for a lightened skyline even on the softest setting but not un-drivable, I was going to have to get use to it for the weekends racing. After lunch and the third practice session the front right disc cracked and sent a shudder through the brake pedal forcing an early end to the practice. We worked out this had occurred due to the fact that the disc was getting quite thin and I was driving through puddles were I could to help keep the wet tyres cool as the track was starting to develop a dry line and the resulting water spraying over a hot thin disc lead to it failing.
This brought about a new problem of trying to find a replacement for the weekends racing, 4pm Friday on Auckland anniversary weekend made for a mad panic rush driving all round Taupo glued to the phone to find a replacement pair of front discs. things were not looking good till I rang a performance shop in Tauranga who had a different brand of disc setup nearly identical to the AP Racing discs with the exception I would need to by the hats as well due to a different bolt pattern. With only a 2mm difference in offset myself and Hayden (crew tech) jumped in the car and drove to Tauranga to pick up the new discs. After a quick stop at an ATM, new discs on board, a quick bite to eat then back to Taupo around 9:30pm after a tyring and busy day of driving I was glad it was over.
First thing Saturday morning we arrived back at the track at 7am and got to work fitting the new brake disc setup, with the only major cahnge making sure the offset of the caliper was in the right place.
No sooner had we finished then I was into my race suit and out on the track for qualifying. for all but two laps I had to take it easy as I needed to bed the new discs in, as a result I put only one flying lap in then cooled the discs down before coming in. the one lap put me in 8th for race one out of 12 GT2 cars A good result.
Race one gave me a 7th place finish with gearbox issues starting to creep in.
Race two was a struggle but all the same I managed a 5th place. During this race the car was starting to fell slippery, I brought this down to probably over driving the tyres a tad and thought nothing more of it.
Race three and the toughest race all season but one of my favorite races, I stuck behind a V8 through the corners only inches behind then come the straight then it was a case of good bye until the infield corners came back round, I would get up besides the car then he would pull away in the short straights between a real cat and mouse race but a lot of fun about half way through the race a loud metallic tapping sound developed, initially my thought was some part of the aero package was about to fall off and I hoped that this was not going to be picked up by the flag marshals forcing me to be flagged in as I was not wanting to give up the fight, after a few more laps the sound started to go and as far as I was concerned the problem had resolved itself and was not affecting the performance so I carried on the chase. Eventually I passed the car when the driver in front made a mistake giving me the chance to get up the inside into the next corner, after the move I pulled a good three to four car lengths through the next two corners taking third place, happy to have clean air in front 0f me I pushed on. I was on track for a potential third when at the very next corner I braked as I normally would and went straight of into the gravel trap. Luckily I was able to dive through and onto the grass on the other side, then drive all the way round the trap back onto the circuit rejoining in last place. The frustrating reality of the situation was when I came round to the finish line the last lap board came out, I new if I had not have gone off then there was a good chance I might have secured third place, but that’s racing for you. When back in the pits I looked over the car to see what the cause of the noise might have been and found everything to be fine, other than when I removed the wheels and noticed the tyres were worn down to the canvas, at this stage I figured out the sound was the tyres belting flicking round inside the guard until it eventually broke off and reviewing the rear facing camera fotage lots of rubber pealing off shooting out the rear of the car. Hmmmm! experience gained.
Overall the weekend was good, I finished all three races, which is more important to achieve than outright positions. As a result I now stand fourth out right in the GT2 championship with more pressure than ever as there is an outside chance of taking third by the end of the season only two rounds away. This will mean finishing all remaining races with no DNF’s and getting good place finishes.
Another issue with the Taupo weekend was the gearbox synchros were virtually shot. This was the gearbox replaced after the first round at Manfeild when the factory box broke and the decision was made to purchase an rb25det box. It turns out after a lot of research and getting to know the difference between the rb20 and 20 boxes, both have pros and cons. The rb20 is lighter and is a far smother, faster and slick changing gearbox but not as strong as the rb25, however given I was putting down 413hp at the rear wheels and running race slicks it still lasted the equivalent of a full season of racing and was the original factory box with 204,000 k’s then put straight into a race car with no work done to it, I was very impressed with it.
On to the rb25 box and one thing is for sure, it will take a lot of power as the gears and shafts are much bigger. However on the bad side of the design, the synchros are far too small as a result they are trying to slow down a large gear and do not like changing quickly, great for a race car right! even with low down changes they have only lasted three rounds with each round getting worse making Taupo very difficult and slowing my lap times by 1.5-2 seconds on average over the rb 20 box. the other problems with the rb25 box is they run very very hot and the oil would go jet black after just one round requiring more frequent oil changes, were as the rb20 was perfectlly clean after two rounds. The only way to help improve the situation is to fit an oil cooler.
Making the decision of which way to go is a difficult one. If I want more hp latter I should stay with the 25 box and accept slow changes and frequent oil changes and synchro rebuilds once a year. Or I get another 20 box and refresh the internals, perhaps shot pein the gears, up the hp by just a little say 50-60hp and take a punt, given I also would like to go to a bigger tyre giving more grip and loading the gearbox even more. Then there is the option of changing to a completely different box altogether and top of the list for bang per buck would be a Tremec T56-magnum, a 6sp close ratio box capable of 700lbf of torque. I guess a no brain-er really as they are surprisingly affordable and I certainly won’t have a problem with gearboxes anymore. Hmmmm! Will have to do some research I think.